Smoking not causally linked to endometrial cancer

Genetic predisposition to smoking does not appear to play an important role in the development of endometrial cancer, a study reports.

Researchers conducted complementary observational and Mendelian randomization (MR) analyses to establish the association between smoking and endometrial cancer risk. They used data from the European Prospective Investigation into Cancer and Nutrition (n=286,415) and the UK Biobank (n=179,271).

For the two-sample MR analyses, a total of 126 and 112 genetic variants robustly associated with lifetime amount of smoking and ever having smoked regularly, respectively, were evaluated in relation to 12,906 cancer patients vs 108,979 noncancer controls from the Endometrial Cancer Association Consortium.

Observational analysis revealed that genetic variants for the lifetime amount of smoking and ever having smoked regularly were both associated with a lower risk of endometrial cancer.

In the MR analysis adjusted for body mass index, genetic predisposition to a higher lifetime amount of smoking had a null effect on the risk of endometrial cancer (odds ratio [OR] per 1-standard deviation increment, 1.15, 95 percent confidence interval, 0.91–1.44).

Likewise, genetic predisposition to ever having smoked regularly showed no association with risk of endometrial cancer.

More studies are needed to elucidate the possible confounders and mechanisms underlying the development of endometrial cancer that may explain its inverse association with smoking.